Prepayment electricity meter
This page on the OkayXairen Wiki is FUCKING SCARY because it goes beep angrily when you're low on electricity.
If you're sensitive to this... Run Away.
A prepayment electricity meter is a type of electricity meter used to ensure people who you think of as being poor pay for their electricity on time, because you don't believe they'll pay for monthly bills.
Usage
In order to add credit onto a prepayment electricity meter, one must first top up their prepayment electricity meter key. This may be accomplished either by visiting your local Post Office, or with a little USB dongle you plug into your PC and use a website to pay money and top up the key. Afterwards, you must insert the key into the meter to tell it that you have money.
Consequences
If you forget to top up the meter, it will begin angrily beeping at you until you feed it. If it remains hungry, it will throw a tantrum, removing electricity from your house. You must then insert the key and press the meter's blue button for a few seconds to tell it you would like to use the secret £5 credit hiding inside the key for emergencies. It will then give you your electricity back and keep beeping until you give it real money again, at which point the secret credit will also be replenished.